<!-- 轮播图组件 -->
<template>
    <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
        <!-- 图片容器 -->
      <ul class="carousel-body">
        <!--  fade 显示的图片-->
        <!--  :class="{fade: index = i}"默认显示索引为0的图片-->
        <li class="carousel-item " v-for="(item, i) in sliders" :key="i" :class="{fade: index === i}">
          <RouterLink :to="item.imgUrl" v-if="item.imgUrl">
            <img :src="item.imgUrl" alt="">
          </RouterLink>
          <!-- 列表轮播 -->
          <div v-else class="slider">
            <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
              <img :src="goods.picture" alt="">
              <p class="name ellipsis">{{goods.name}}</p>
              <p class="price">&yen;{{goods.price}}</p>
            </RouterLink>
          </div>
        </li>
      </ul>
      <!-- 上一张 -->
      <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
      <!-- 下一张 -->
      <a @click="toggle(1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
      <!-- 指示器 -->
      <div class="carousel-indicator">
        <!-- active激活点 -->
        <span @click="index = i" v-for="(item, i) in sliders"  :key="i" :class="{active: index === i}"></span>
      </div>
    </div>
  </template>
  
  <script>
import { ref, watch } from 'vue'
  export default {
    name: 'XtxCarousel',
    //接收轮播图数据
    props: {
        sliders: {
            type: Array,
            default: () => []
        },
        //控制是否自动轮播
        autoPlay: {
            type: Boolean,
            default: false
        },
        //间隔时长
        duration: {
            type: Number,
            default: 3000
        }
    },
    setup (props) {
        // 控制显示图片的索引
        let index = ref(0)
        //自动轮播
        let timer = null
        const autoPlayFn = () => {
            //清除定时器，防止重复添加
            clearInterval(timer)
            timer = setInterval(() => {
                index.value++
                if(index.value >= props.sliders.length) {
                    index.value = 0
                }
                
            }, props.duration)
        }
        // 监听sliders数据变化, 判断如果有数据且autoplay为true时
        watch(() => props.sliders, (newVal) => {
            if(newVal.length && props.autoPlay) {
                autoPlayFn()
            }
        }, {immediate: true})
        //鼠标进入，停止播放，鼠标离开，继续播放
        const stop = () =>{
            if(timer) clearInterval(timer)
        }
        const start = () =>{
            if(timer) autoPlayFn()

        }
        //点击点切换图片
        //点击指示器，切换上一张/下一张
        const toggle = (step) => {
            //将要切换图片的索引
            const newIndex = index.value + step
            // 超出情况
            if(newIndex >= props.sliders.length) {
                index.value = 0
                return
            }
            //小于情况
            if(newIndex < 0) {
                index.value = props.sliders.length - 1
                return
            }
            // 正常情况下
            index.value = newIndex
        }
        return {index, stop, start, toggle}
    }
    

  }
  </script>
  <style scoped lang="less">
  .xtx-carousel{
    width: 100%;
    height: 100%;
    min-width: 300px;
    min-height: 150px;
    position: relative;
    .carousel{
      &-body {
        width: 100%;
        height: 100%;
      }
      &-item {
        width: 100%;
        height: 100%;
        position: absolute;
        left: 0;
        top: 0;
        opacity: 0;
        transition: opacity 0.5s linear;
        &.fade {
          opacity: 1;
          z-index: 1;
        }
        img {
          width: 100%;
          height: 100%;
        }
      }
      &-indicator {
        position: absolute;
        left: 0;
        bottom: 20px;
        z-index: 2;
        width: 100%;
        text-align: center;
        span {
          display: inline-block;
          width: 12px;
          height: 12px;
          background: rgba(0,0,0,0.2);
          border-radius: 50%;
          cursor: pointer;
          ~ span {
            margin-left: 12px;
          }
          &.active {
            background:  #fff;
          }
        }
      }
      &-btn {
        width: 44px;
        height: 44px;
        background: rgba(0,0,0,.2);
        color: #fff;
        border-radius: 50%;
        position: absolute;
        top: 228px;
        z-index: 2;
        text-align: center;
        line-height: 44px;
        opacity: 0;
        transition: all 0.5s;
        &.prev{
          left: 20px;
        }
        &.next{
          right: 20px;
        }
      }
    }
    &:hover {
      .carousel-btn {
        opacity: 1;
      }
    }
  }
  // 轮播商品列表
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
  </style>
  